Merge to XFA: CPDF_Parser shouldnt be in the business of opening files

(cherry picked from commit 2b9178181eb82a3611bee5c9435ea5956def24be)
Orignal Review URL: https://codereview.chromium.org/1269073003 .

TBR=thestig@chromium.org

Review URL: https://codereview.chromium.org/1278533002 .
3 files changed